1. Field of the Invention
This invention relates to a device and method for adding chemicals to a producing oil and gas well to enhance production. This invention also relates to a method and apparatus for choking a fluid flow path.
2. Background of the Invention
This invention relates to a device and method for efficiently and reliably adding chemicals, on a continuous basis, to a producing oil and gas well to eliminate undesirable conditions such as paraffin build-up, corrosion, and the like.
In a typical oil and gas well, oil is pumped upwardly through a central tubing string by either a sucker-rod type pump or by a downhole pump. The tubing string is surrounded by casing. Gas typically travels upwardly through the casing. Oil and gas enter the tubing and casing from the formation through perforations in the casing. Perforations are subject to plugging, and the pump and tubing are subject to build-up of scale and damage by corrosion.
In general, a producing oil well is subject to emulsion or paraffin build-up, build-up of scale within the tubing, and corrosion. Without treatment these conditions can reduce or stop production.
In the case of paraffin build-up, it is a common industry practice to periodically treat the well with hot oil, trucked to the site. The truck pumps hot oil down the casing and back up the tubing. This process removes deposits of paraffin by melting the paraffin. A triplex injection truck is also used to treat downhole corrosion and scale problems. The truck batch-treats the well by pumping chemicals down the casing and back up the tubing using typically three or four barrels of water to flush the chemicals down the casing. The truck must inject several gallons of chemicals per treatment to have the desired effect.
A slip stream device is described and claimed in U.S. Pat. Nos. 4,796,697 and 4,896,726. The slip stream device is adapted to automatically and continuously inject well treatment chemicals to a producing oil and gas well. This slip stream device uses a small amount of the production fluids (including oil and water) as a carrier for production enhancing chemicals. In this device, a small amount of production fluid is diverted to a mixing chamber, and mixed with a selected performance-enhancing chemical. The mixture is directed into the well on an automatic and continual basis.